Final Score Power Index - an objective evaluation of NFL teams, based on final scores of games played.

Friday, December 12, 2008

Division Power and Super Bowl Winners

Division Power and FWDP

APR
already gives a way to compute a power index for individual
teams. Division power can be computed by averaging teams power
index on a per-division basis.

Just as team power indexes can be computed for each week of the
regular season, division power indexes can be computed for each week
as well. For the purposes of analyzing the division power of Super
Bowl winners, I will use the division powers from the final week of
the regular season.

For the purpose of future discussion, I will abbreviate Final Week
Division Power as FWDP.

Super Bowl Contestants by Division Power

The
the list of the strongest divisions by FWDP since 1960 has the
divisions of lot of Championship and Super Bowl winning teams on
it. Which naturally suggests there might be a correlation between
strong FWDP and winning the Super Bowl.

Looking at the seasons from 1990 to 2007, there appears to be a
very strong correlation between strong FWDP and winning the Super
Bowl:

Year

HighFWDP

Result

LowFWDP

1990

New YorkGiants

beat

BuffaloBills

1991

WashingtonRedskins

beat

BuffaloBills

1992

DallasCowboys

beat

BuffaloBills

1993

DallasCowboys

beat

BuffaloBills

1994

San Francisco49ers

beat

San DiegoChargers

1995

DallasCowboys

beat

PittsburghSteelers

1996

Green BayPackers

beat

New EnglandPatriots

1997

Green BayPackers

lost to

DenverBroncos

1998

AtlantaFalcons

lost to

DenverBroncos

1999

TennesseeTitans

lost to

St. LouisRams

2000

BaltimoreRavens

beat

New YorkGiants

2001

New EnglandPatriots

beat

St. LouisRams

2002

OaklandRaiders

lost to

Tampa BayBuccaneers

2003

New EnglandPatriots

beat

CarolinaPanthers

2004

New EnglandPatriots

beat

PhiladelphiaEagles

2005

PittsburghSteelers

beat

SeattleSeahawks

2006

IndianapolisColts

beat

ChicagoBears

2007

New YorkGiants

beat

New EnglandPatriots

That's a 14-4 record (77.7%) for that span of games, which suggests
that FWDP is a strong indicator of which team wins the Super
Bowl.

Something Happened in 1990

I chose the cut-off year of 1990 advisedly. The results from 1970
to 1989 are quite different:

Year

HighFWDP

Result

LowFWDP

1970

DallasCowboys

lost to

BaltimoreColts

1971

DallasCowboys

beat

MiamiDolphins

1972

WashingtonRedskins

lost to

MiamiDolphins

1973

MiamiDolphins

beat

MinnestoaVikings

1974

PittsburghSteelers

beat

MinnesotaVikings

1975

PittsburghSteelers

beat

DallasCowboys

1976

MinnesotaVikings

lost to

OaklandRaiders

1977

DenverBroncos

lost to

DallasCowboys

1978

PittsburghSteelers

beat

DallasCowboys

1979

PittsburghSteelers

beat

Los AngelesRams

1980

OaklandRaiders

beat

PhiladelphiaEagles

1981

CincinnatiBengals

lost to

San Francisco49ers

1982

WashingtonRedskins

beat

MiamiDolphins

1983

WashingtonRedskins

lost to

Los AngelesRaiders

1984

San Francisco49ers

beat

MiamiDolphins

1985

New EnglandPatriots

lost to

ChicagoBears

1986

DenverBroncos

lost to

New YorkGiants

1987

WashingtonRedskins

beat

DenverBroncos

1988

CincinnatiBengals

lost to

San Francisco49ers

1989

San Fracisco49ers

beat

DenverBroncos

That's a 11-9 record (55.0%) for that span of games, which
suggests that there is little or no correlation between FWDP and which teams
won the Super Bowl during that era.

What Happened in 1990?

If you've followed the NFL for any length of time, you know that
they are constantly changing the rules. Often to protect the safety
of the players, or to make the game more exciting.

A number of significant changes were made during this era. Free
agency and the salary cap were introduced. The post-season was
expanded from 5 playoff teams per conference to 6.

I would like to have a definitive answer to put here. However, given
the small sample space, the number of rule changes, and the fact
that there's no way to "replay" old seasons with different
rules, it's probably impossible to say what caused the change.

I would also like to be able to make some claim that the 1990-2007
correlation will continue in the future. But with no specific
cause to point to, there's no way to make the case that some
subsequent change won't undo (or hasn't already undone) the
effect.

The Future

Following the final week of the 2008 season (and for each future
season I keep FSPI going), I will post the FWDP for all 8
divisions. In the pick result post following the Super Bowl, I will
link back to the FWDP post, note whether or not the team with
the better FWDP index won, and update the 1990-present tally.